Manual machine tools and automatic machine tools, such as numerical control (NC) machines, are widely used nowadays. Since NC machines are very expensive and manual machine tools are not effective, a stroke controlling mechanism, such as a cam shaft which carries a number of cams; is provided for controlling the strokes of a number of tools so that the tools can machine a workpiece automatically.
One of the major limitations of such a machine tool using the stroke controlling mechanism is the procedure of fitting the cams on the cam shaft. The cams must be accurately aligned on the cam shaft in order to maintain a certain accuracy. The alignment of the cams on the cam shaft as known in prior art, has been done by the trial and error method. A sample is first machined and then measured to establish the variance from the required size. The cams are then adjusted accordingly until an accurate workpiece of the required size is produced. Normally, it takes hours to adjust the cams on one cam shaft. If two or more sets of cams are required for machining a workpiece, a more complex process and a much longer time are required to adjust the cams. In addition, the cams must be adjusted and/or the tools must be replaced in order to machine different workpieces. Therefore, the trial and error method must be used again and again, which is uneconomical and impractical.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the stroke controlling mechanism of machine tools.